Overview
This repository provides code and sample data to estimate the effect of single state’s policy on birth outcomes using the augmented synthetic control method (ASCM) utilizing the augsynth package. This report displays select results and their corresponding diagnostic tables and plots.
The policy exposure in this example is Texas Senate Bill 8 (TX SB 8), a 6 week gestational ban on abortion that went into effect on September 1, 2021.
All results are generated using synthetic data and therefore are for educational purposes only.
Cohort definition
Inclusion criteria
- All births and fetal deaths beginning January 1, 2014
Exclusion criteria
- Singleton births and fetal deaths
- Gestational age \(\geq\) 20 weeks
- Removed Connecticut records due to undercounting of fetal deaths
- Removed Virginia due to record quality (maternal morbidity outcomes only, not shown in this report)
Exposure definitions
Exposure 1: policy implemented by at least 6 weeks gestation
Pregnancies are exposed if, by the date the policy went into effect, the pregnancy was at least 6 weeks gestational age.
- Pregnancies where the stillbirth or birth occurred before the policy went into effect are unexposed
- Pregnancies that were under 6 weeks gestational age by the date the policy went into effect are removed from the analysis (i.e., only looking at the first cohort of pregnancies)
Due to the nature of preterm births, for this exposure definition observations on or before April 1, 2022 for this analysis need to be removed.
Exposure 2: policy implemented at any time during pregnancy
Pregnancies are considered exposed if the policy was in effect for any portion of the pregnancy.
- Pregnancies where the stillbirth or birth occurred before the policy went into effect are unexposed
- No additional pregnancies are removed
Due to other states receiving the treatment (i.e., causing unbalanced data) the post-treatment period ends at May 1, 2022.
Outcomes
- Stillbirth rate
- Preterm birth rate, conventional approach: live births are only included in the denominator
- Preterm birth rate, “fetus-at-risk approach”: live births and stillbirths are included in the denominator
Time-varying confounders
- State Medicaid expansion
- State proportion of pregnancies where maternal age \(\geq\) 35 at the time of the stillbirth or birth
Results and ASCM diagnostics
Exposure 1: policy implemented by at least 6 weeks gestation
Stillbirth
Stillbirth ATT
| 0 |
0.036 |
-0.170 |
0.242 |
0.824 |
| 1 |
0.154 |
-0.052 |
0.360 |
0.355 |
| 2 |
0.138 |
-0.068 |
0.344 |
0.351 |
| 3 |
-0.129 |
-0.335 |
0.077 |
0.408 |
| 4 |
-0.016 |
-0.222 |
0.190 |
0.933 |
| 5 |
-0.027 |
-0.233 |
0.179 |
0.847 |
| 6 |
-0.112 |
-0.318 |
0.094 |
0.509 |
Stillbirth observed and synthetic summary
| Period |
Months |
Mean |
SE |
Lower CI |
Upper CI |
Mean |
SE |
Lower CI |
Upper CI |
| Post-Policy |
7 |
0.515 |
0.035 |
0.429 |
0.60 |
0.508 |
0.023 |
0.452 |
0.565 |
| Pre-Policy |
92 |
0.527 |
0.016 |
0.495 |
0.56 |
0.527 |
0.007 |
0.514 |
0.541 |
Stillbirth RMSE
| 0.006 |
0.138 |
Preterm birth, conventional approach
PTB ATT
| 0 |
0.276 |
-0.359 |
0.912 |
0.492 |
| 1 |
0.128 |
-0.507 |
0.763 |
0.755 |
| 2 |
-0.181 |
-0.816 |
0.455 |
0.688 |
| 3 |
0.559 |
-0.076 |
1.194 |
0.081 |
| 4 |
0.218 |
-0.417 |
0.853 |
0.647 |
| 5 |
-0.104 |
-0.740 |
0.531 |
0.893 |
| 6 |
0.459 |
-0.177 |
1.094 |
0.241 |
PTB summary
| Post-Policy |
7 |
11.739 |
0.219 |
11.203 |
12.275 |
11.545 |
0.210 |
11.030 |
12.060 |
| Pre-Policy |
92 |
11.080 |
0.083 |
10.916 |
11.245 |
11.080 |
0.072 |
10.938 |
11.223 |
Preterm birth, fetus-at-risk approach
PTB FAR ATT
| 0 |
0.281 |
-0.355 |
0.916 |
0.416 |
| 1 |
0.142 |
-0.493 |
0.778 |
0.742 |
| 2 |
-0.179 |
-0.815 |
0.456 |
0.714 |
| 3 |
0.570 |
-0.065 |
1.206 |
0.088 |
| 4 |
0.215 |
-0.421 |
0.851 |
0.633 |
| 5 |
-0.121 |
-0.757 |
0.515 |
0.899 |
| 6 |
0.436 |
-0.200 |
1.072 |
0.230 |
PTB FAR summary
| Post-Policy |
7 |
11.703 |
0.217 |
11.173 |
12.234 |
11.511 |
0.204 |
11.013 |
12.010 |
| Pre-Policy |
92 |
11.033 |
0.083 |
10.868 |
11.197 |
11.033 |
0.072 |
10.891 |
11.175 |
Exposure 2: policy implemented at any point in pregnancy
Stillbirth
Stillbirth ATT
| 0 |
-0.396 |
-0.797 |
0.000 |
0.054 |
| 1 |
0.227 |
-0.109 |
0.546 |
0.239 |
| 2 |
0.134 |
-0.217 |
0.470 |
0.412 |
| 3 |
0.298 |
-0.070 |
0.667 |
0.135 |
| 4 |
0.032 |
-0.353 |
0.433 |
0.818 |
| 5 |
0.058 |
-0.326 |
0.443 |
0.769 |
| 6 |
0.040 |
-0.345 |
0.441 |
0.849 |
| 7 |
0.007 |
-0.377 |
0.375 |
1.000 |
Stillbirth observed and synthetic summary
| Period |
Months |
Mean |
SE |
Lower CI |
Upper CI |
Mean |
SE |
Lower CI |
Upper CI |
| Post-Policy |
8 |
0.648 |
0.070 |
0.484 |
0.813 |
0.598 |
0.014 |
0.565 |
0.632 |
| Pre-Policy |
92 |
0.568 |
0.018 |
0.533 |
0.603 |
0.568 |
0.007 |
0.554 |
0.581 |
Stillbirth RMSE
| 0.05 |
0.139 |
Preterm birth, conventional approach
PTB ATT
| 0 |
0.277 |
-0.487 |
1.041 |
0.480 |
| 1 |
0.138 |
-0.626 |
0.902 |
0.747 |
| 2 |
-0.148 |
-0.913 |
0.616 |
0.801 |
| 3 |
0.577 |
-0.125 |
1.341 |
0.099 |
| 4 |
0.226 |
-0.538 |
0.990 |
0.652 |
| 5 |
-0.031 |
-0.795 |
0.733 |
0.987 |
| 6 |
0.772 |
0.000 |
1.536 |
0.069 |
| 7 |
0.263 |
-0.501 |
1.027 |
0.645 |
PTB observed and synthetic summary
| Period |
Months |
Mean |
SE |
Lower CI |
Upper CI |
Mean |
SE |
Lower CI |
Upper CI |
| Post-Policy |
8 |
12.101 |
0.144 |
11.762 |
12.441 |
11.842 |
0.089 |
11.632 |
12.052 |
| Pre-Policy |
92 |
11.080 |
0.083 |
10.916 |
11.245 |
11.080 |
0.072 |
10.937 |
11.223 |
Preterm birth, fetus-at-risk approach
PTB FAR ATT
| 0 |
0.279 |
-0.481 |
1.040 |
0.505 |
| 1 |
0.151 |
-0.610 |
0.881 |
0.737 |
| 2 |
-0.146 |
-0.906 |
0.615 |
0.765 |
| 3 |
0.585 |
-0.175 |
1.346 |
0.078 |
| 4 |
0.237 |
-0.524 |
0.998 |
0.633 |
| 5 |
-0.035 |
-0.796 |
0.725 |
0.982 |
| 6 |
0.755 |
-0.006 |
1.516 |
0.074 |
| 7 |
0.255 |
-0.506 |
1.015 |
0.637 |
PTB FAR observed and synthetic summary
| Period |
Months |
Mean |
SE |
Lower CI |
Upper CI |
Mean |
SE |
Lower CI |
Upper CI |
| Post-Policy |
8 |
12.055 |
0.143 |
11.717 |
12.394 |
11.795 |
0.088 |
11.586 |
12.004 |
| Pre-Policy |
92 |
11.033 |
0.083 |
10.868 |
11.197 |
11.033 |
0.072 |
10.890 |
11.175 |